Plastic and nonmetallic article shaping or treating: processes – Formation of solid particulate material directly from molten... – By extrusion spraying or gravity fall through orifice
Reexamination Certificate
1999-10-19
2001-08-21
Tentoni, Leo B. (Department: 1732)
Plastic and nonmetallic article shaping or treating: processes
Formation of solid particulate material directly from molten...
By extrusion spraying or gravity fall through orifice
C264S109000
Reexamination Certificate
active
06277310
ABSTRACT:
This invention relates means for and methods of protecting the dimensional stability of fibers (especially fiber composite panels such as oriented strand board, for example) by increasing the resistance to an absorption of moisture and to swelling when in the presence of water. More particularly, this invention relates to an accomplishment of such increased moisture resistance through a use of renewable agricultural or animal products, as distinguished from the use of a depleting resource, such as petroleum based products.
Reference is made to U.S. Pat. No. 5,607,633, granted Mar. 4, 1997, which describes a “Co-Adhesive System for Bonding Wood, Fibers or Agriculture Based Composite Materials” and to my co-pending application, 08/472,919, filed Jun. 7, 1995, and entitled “Method of Conjugating Double Bonds in Drying Oils”, now U.S. Pat. No. 5,719,301 granted Feb. 17, 1998. This patent and application describe the use of natural oils containing more than one carbon to carbon double bond. The double bonds are generally separated by a methylene group, commonly described as “methylene interrupted”. Double bonds adjacent to one another are “conjugated” (i.e., the methylene interrupt is shifted or relocated).
A simple explanation of methylene interrupt shift is illustrated by the following example showing only carbon atoms:
—C═C—C—C—C——C═C—C═C—C—
The carbon chain on the left is methylene interrupted between the two carbon atoms having double bonds. The carbon chain on the right is conjugated by shifting the methylene group to the end of the chain of carbon atoms.
Vegetable oils or animal fats hydrogenated to low or very low iodine values (“IV”), also known as iodine numbers, or fats naturally composed primarily of saturated triglycerides (such as palm oil or fractionated fats) can be used alone or in blend formulations with adhesives/laminants to achieve an enhanced water tolerance for composite materials.
The iodine values or numbers are a measure of the iodine absorbed in a given time by a chemically unsaturated material, such as a vegetable oil and is used to measure the unsaturation or number of double bonds of a compound or mixture. Examples of saturated triglycerides having a low iodine value (a range of Iodine Values of about 0-70 with 0-30 preferred) may be produced by a hydrogenation of a commercial oil or fat, such as oils of: soybean, soy stearine, stearine, corn, cottonseed, rape, canola, sunflower, fish, lard, tallow, palm, palm kernel, coconut, crambe, linseed, peanut, tall oil, animal fats, and blends thereof. These oils may also be produced from genetically engineered plants to obtain low IV oil with a high percentage of fatty acid.
The invention may be used with composite materials which generally include wood, fibers, and other agricultural materials and may also contain non-agricultural based fillers and the like such as recycled plastics, etc. Example of such composites are: particle board, plywood, oriented strand board (“OSB”), medium density fiberboard, hardboard, formed molded shapes, etc. Adhesives and laminants alone or synergistically blended together are used to bond these materials into desired forms such as panels, structural shapes, etc. Laminants/adhesives may include phenol formaldehyde, resol/phenol formaldehyde, urea-formaldehyde, isocyanate, MDI, polyvinyl acetate, protein and other resins, melamine-urea-formaldehyde, di-isocyanate resorcinol-phenol formaldehyde, protein, tannin-formaldehyde, sulfite liquor, conjugated linseed oil, and combinations of these.
Generally, a petroleum based product known as slack wax is available in either a powdered or emulsified form and is used to enhance moisture tolerance in these and similar composite materials. However, it contains a wide range of compounds with varying degrees of volatility. Also, slack wax suffers from being a non-renewable by-product of the petroleum industry.
The manufacture of certain products based on plant life can produce a concentration of volatile organic compounds (“VOC”) which become serious pollutants. Therefore, in the manufacture of any product, such as this invention, a limitation upon the output of the VOC's becomes very important. Federal, state and locate regulations severely limit the release of VOC's for example, see the EPA Clean Air Act.
The above-mentioned composites are subjected to a hot press cycle during their manufacture. When so subjected to this hot press cycle, slack wax products significant amounts of volatile organic carbons (“VOC”). These VOC's present a hazard to workers in the press area and a substance emission problem for the plants producing the composites. Very frequently, the VOC's cause fire hazards in the exhaust flues and stacks.
According to my invention and use of low iodine value (“IV”) triglyceride fats, all of the above problems are solved or greatly reduced whole providing the desired benefits of increased moisture tolerance. Low IV fat has virtually no volatility under the conditions used for pressing composites and does not present any problem or hazard. Thus, it contributes no or virtually no VOC's to the process, thereby reducing the total plan VOC emissions from the manufacturing process for making OSB and the like. Also, stack fires and worker exposure are reduced.
The invention has an outstanding additional benefit. It is made from a totally renewable agricultural resource and as such is what is known as a “green” product. In fact, almost any triglyceride oil (especially those oils found in common commerce) containing double bonds may be hydrogenated to produce a low IV fat. In general, the commodity price of the oil will dictate which is preferable at any given time since the oils are generally interchangeable and the lowest cost is usually the determining factor.
Additionally, a range of iodine values or degrees of completeness of hydrogenation have been found to provide water tolerance. This ability to enhance tolerance was found to decrease with increasing IV. However, the costs of hydrogenation, such as the cost of catalyst usage, reaction time, etc., must also be considered. Therefore, an optimal product having a lowest cost of product versus optimum performance may be the most advantageous.
Fats are commonly fractionated usually by a process known as “winterization” wherein they are chilled for a period of time which is long enough to allow the harder fractions of the fats to crystallize. This chilling is followed by filtration with the harder fractions being retained on a filter cake. These harder fractions have a lower iodine value and, therefore, a melting point that is higher than the melting point of the fat from which it has been separated. Hence, winterization can be used as a source for lower IV fats.
In general, my invention may be used in the form of a spray of melted liquid, or of chilled (prilled), ground, cryo-ground or micro-crystallized powder having a particle size generally passing through a U.S. #100 screen (0.14 mm) or smaller.
In a preferred embodiment, triglyceride or the fat is melted to form a liquid which is sprayed directly onto the fiberous materials used to form the composite boards, such as: wood, fibers, agricultural materials, or the like. The melted liquid triglyceride may be combined with a bonding agent or adhesive such as urea-formaldehyde, melamine-urea formaldehyde, di-isocyanate resorcinol-phenol-formaldehyde, protein, tannin-formaldehyde, sulfite liquor and conjugated linseed oil and any combination thereof.
The melted liquid triglyceride may be combined with the bonding agent or adhesive either before the melted liquid is sprayed or the fiberous material or the liquid and bonding agent may be combined by being separately and sequentially sprayed on the fiberous material.
Spray prilling may be accomplished by melting the fat and spraying it through either a nozzle of proper configuration or a spinning disk atomizer in order to provide a fine powder as it then solidifies in cool air. It may also be made by grinding with cryo-grinding preferred.
Altern
Archer Daniels Midland Company
Laff, Whitesel & Saret, Ltd.
Tentoni Leo B.
Whitesel J. Warren
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